Government inspectors failed to take action on one of every five serious food-safety risks identified in manufacturing facilities, according to a report released by federal auditors Wednesday. In the remaining cases, the agency almost always asked food manufacturers to correct violations voluntarily.

In one incident in 2013, FDA inspectors found listeria in a facility where rain dripped through holes in the ceiling onto food prep areas. While FDA asked the facility to address the problems, samples from the factory still tested positive for listeria two years later.

That same year, FDA inspectors found salmonella in a facility that made ready-to-eat seafood, salads and dips. But they did not send the facility a warning letter or initiate any other corrective actions.

The Department of Health and Human Services’ Office of Inspector General report, which analyzed Food and Drug Administration inspection data from 2011 to 2015, raises questions about FDA procedures for making sure America’s food is safe. It has also prompted concerns as to whether the agency has the resources to fulfill the objective.

FDA’s mission has broadened considerably since the implementation of a 2011 law called the Food Safety Modernization Act, which made it mandatory for the agency to carry out routine inspections of all domestic food processors.

But the agency’s total funding decreased over that same period, and employment in the Office of Regulatory Affairs — the branch of the FDA that is primarily responsible for conducting field inspections — had increased by only 11 percent as of 2013, the most recent year for which data is available.

Now, some food-safety experts are questioning whether federal food-safety funding has kept pace with the expansion of the agency’s mission.

“If you want a very robust inspection program, you have to have very robust funding,” said Sandra Eskin, who heads the food safety program at Pew Charitable Trusts. Whether or not FDA has that funding is, Eskin said, “an issue that deserves more attention.”

In a statement, FDA acknowledged the issues in its inspection process and committed to improving them. The agency “recognizes the importance of its oversight of domestic food facilities,” the statement added.

That oversight has expanded in recent years, to include enforcement powers the agency never had before.

While FDA has long overseen the safety of most foods in the U.S. — meat, poultry and eggs are the exception — the 2011 law required far more regular inspections of domestic food processors, even those that are considered low-risk.

Meanwhile, the number of such facilities grew. There were just under 76,000 food processing facilities in 2011, according to FDA figures. There were more than 86,000 in 2015, an increase of 13 percent.

FDA declined to provide figures for inspector growth over that period. But the agency’s past appropriations requests suggest it may have struggled to ramp the program up quickly. As recently as the 2016 fiscal year, FDA requested an additional $18.7 million for food safety training, writing that the agency would be unable to “ensure effective and consistent inspections” without the funding.

In 2017, the agency requested $11.3 million for its National Integrated Food Safety System to train state inspectors, among other things.

Inspectors are responsible for visiting a wide range of food processors — from tofu-makers to flour-millers to coffee roasters — and making sure that they follow rules on cleanliness, facility construction, employee hygiene and storage.

When agency inspectors visit a facility, they look for visible signs of insects, rodents and poor sanitation, as well as review the company’s food safety paperwork and take swabs for lab analysis. FDA is supposed to follow-up with the manufacturer to make sure safety issues are addressed.

But that is not always the case, OIG auditors found. Of the 1,535 major food-safety violations that inspectors documented between 2011 and 2015, FDA took action on only 78 percent — effectively ignoring more than 300.

“These inspections are essential. The follow-up is essential,” said Jodi Nudelman, a regional inspector general for the Department of Health and Human Services and an author of the new report. “That’s how you ensure a safe food supply — and we found a number of really serious problems.”

Even when the agency did respond to a severe food-safety violation, Nudelman said, it didn’t always result in change.

Auditors found that FDA relies almost exclusively on warning letters and regulatory meetings to bring food-safety issues to the attention of food companies. While the vast majority of manufacturers take such “advisory actions” seriously, they are not legally obligated to address issues raised in an advisory letter — and OIG found that many didn’t.

Of 766 facilities that received “advisory” actions, for instance, one in five still had significant violations months or years later. And that figure may underestimate the total number of facilities that never addressed major problems, Nudelman added, because FDA regularly fails to reinspect facilities that have been flagged for food-safety violations.

“The most concerning thing to me is the lack of follow-up on the violations they find,” said Thomas Gremillion, the head of food policy at the Consumer Federation of America, a consumer advocacy group. “They were just taking industry’s word that they’d corrected the problems . . . and in many cases, they hadn’t.”

Gremillion and other food-safety experts cautioned that the report’s findings doesn’t necessarily indicate that America’s food supply unsafe. FDA inspections are just one piece of a large, complex food-safety system, which also includes state and local health departments, other federal agencies, and food producers and processors themselves.

This report also only looked at one sector of the food supply: processed foods. Outbreak data from the Centers for Disease Control and Prevention indicates that more foodborne illnesses originate with things like fresh produce.

Still, experts say, the report raises serious questions about how FDA has conducted food-safety inspections — and whether the agency has, or will ever have, the resources to meet the new inspection thresholds set in 2011. President Trump’s budget proposal, released in late May, called for nearly $83 million in cuts to FDA’s food-safety program, with the bulk of those cuts hitting inspectors.

Lauren Sucher, an FDA spokesman, said that the agency “will continue to work to fulfill our mission to the best of our ability with the resources allocated.”

But some in Congress have already seized the OIG report as evidence that food safety programs are underfunded.

“It is clear that the FDA needs more resources to efficiently and effectively inspect food facilities and enforce infractions to keep our food supply safe,” said Rep. Rosa DeLauro, D-Conn., a leading food-safety advocate, in a statement. “It is the responsibility of the FDA to ensure that American consumers can trust the safety of food they consume.”

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